Electrical clip contact device



Aug. 23, 1966 B. WENNERSTEN 3,268,852

ELECTRICAL CLIP CONTACT DEVICE Filed March 11, 1965 United States Patent3,268,852 ELECTRICAL CLIP CONTACT DEVICE Bo Wennersten, Medsolbacken 15,Vallingby, Sweden Filed Mar. 11, 1965, Ser. No. 438,901 Claims priority,application Sweden, Mar. 16, 1964, 3,236/64 6 Claims. (Cl. 339258) Thepresent invention relates to an electrical contact device of the cliptype in which the two parallel legs of the clip are adapted to clampbetween them a contact blade. The invention, more particularly, has forits object to provide such contact devices with an arrangement adaptedsimultaneously to fulfil two functions, namely to increase the contactpressure by which the two legs of the clip clamp the contact bladebetween them, and to positively prevent the blade from inadvertentlyleaving its closed position. The principal object of the invention maybe stated as being the provision of an arrangement not only combining initself the dual functioning just described but also being structurallysimple whereby it is cheap to manufacture and convenient in handling aswell as safe in operation.

Several devices are previously known which fulfil the first-mentionedfunction, i.e. to increase the contact pressure between the clip andblade. However, all these priorart constructions have in common thedrawback of being relatively complex and bulky, primarily for the reasonthat they were always so designed that the contact-pressure producing oraugmenting force gives rise to a reaction force which will have to betaken up by some structural element or other included for thisparticular purpose and being in the form of a frame or support which wasrigidly connected with the body of the electrical apparatus concernedwith which the clip contact is associated. A specific object of theinvention is the provision of an arrangement capable of producing anincreased contact pressure against said contact blade with out thenecessity of transmitting the corresponding reaction forces to any partoutside the contact clip, said reaction forces being instead absorbed orneutralised in this clip proper.

A third object of the invention is to provide means completely or partlyintegral with the arrangement referred to in the last-precedingparagraph and adapted purely mechanically, or positively, to prevent thecontact blade from inadvertently leaving its closed position. This couldoccur for any of two principal reasons. The first one involves that theposition of the blade is disturbed by any direct mechanical actionthereon, such as in the form of vibrations or impacts. One usual case ofthis type occurs when the contact blade forms part of, for example, abridge fuse mounted on a movable contact bridge of a fuse switch. Thesecond main cause of an inadvertent disengagement of the contact bladefrom its operative position depends on the excessive electromagneticalforces produced as the currentfor instance when short-circuiting takesplaceattains very high values and, due to the configuration of thecurrent path concerned, tending to throw out the fuse or correspondingmember from its contact clips.

The mainly characterizing feature of the arrangement of the inventionresides in that it comprises an element which is movable between a firstposition in which the opening between the two extreme ends of the cliplegs is unobstructed, and a second position in which said element isadapted both to obstruct said clip opening thereby preventing thecontact blade from moving out through the same, and to augment thecontact pressure between the blade and each of the clip legs.

One embodiment of the invention will be described hereinafter withreference to the accompanying diagrammatic drawing, in which:

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FIG. 1 is an end view of a contact clip provided with an arrangementaccording to the invention, said movable element being shown in aposition in which the contact blade is latched against getting thrownout of engagement, but in which the second main function, i.e. theaugmentation of contact pressure, is not attained;

FIG. la illustrates the device of FIG. 1 in a View at right anglesthereto;

FIGS. 2 and 2a correspond to FIGS. 1 and la, respectively, with theexception that in the present case said movable element is in itscontact-pressure augmenting position;

FIG. 3 is a view of the device corresponding to those of FIGS. la and2a, respectively, but with the movable element in its completely openposition, i.e. in a position in which it will afford neither anylatching action nor any increase of the contact pressure.

Numeral 1 designates a clip contact member having two legs or jaws 2 and3. These legs clamp between them a blade contact member or blade 4 whichis presumed to form a part of an electrical apparatus, such as a bridgefuse, for example. The free ends of the clip legs 2 and 3 are bent outsubstantially perpendicularly to the flat sides of the contact blade 4.These laterally extending portions of the legs have been denoted by 5and 6, respectively. Leg portion 5 carries a pin 7 having a cylindricalhead 8 provided with a screw driver slot and journalled in a hole madein leg portion 5. Leg portion 6 is provided with a large stud 9 beingalso provided with a head, as shown. Pivoted on the pin 7 is a somewhathook-like element 10 the notch 11 of which is intended to cooperate withstud 9. The portion of pin 7 disposed between leg portion 5 and pin head8-is provided with an eccentric 12 intended to cooperate with an openingmade in the hook-like element 10.

The arrangement thus described operates as follows. After the contactblade 4 has been moved into its closed position, during which operationthe hook 10 should, of course, be in its angular position shown in FIG.3, the hook is moved into its position shown in FIG. 1. Then, by meansof a screw driver, the pin 7 is rotated whereby, by cooperation of theeccentric 12 with the associated opening in the hook 10, the latter willbe positively forced in the left-hand direction. After engagement havingbeen reached between the inner edge surface of the extreme end portion13 of the hook and the stud 9, a continued rotation of pin 7, obviously,will cause the contact blade 4 to be increasingly forcefully clampedbetween the legs 2 and 3.

According to more specific features of the invention, the device issuitably provided with elements in the form of stop lugs which willfacilitate its handling. Numeral 14 designates such a stop lug. Thelatter should be placed in a position such that, when the pin head 8 hasbeen moved into engagement with the same, thereby restraining continuedturning of the pin, the eccentric 12 should occupy the position in whichmaximum contact pressure is afforded between the clip legs 2, 3 and thecontact blade 4. Disposed at the diametrically opposite side of the pinhead is a similar stop lug 15. The purpose of the latter is to ensurethat, after the pin having been rotated in a contact-pressure relievingsense until the pin head 8 has engaged said stop lug, a continuedturning of the pin in the same sense, i.e. counter-clockwise in theexemplary embodiment shown, shall result in carrying the hook 10 intothe open position thereof as illustrated in FIG. 3. This in its turn isdefined by a third stop lug 16 which is bent up from the extreme end ofthe bent-out portion 5 of the clip contact leg 2 (FIG. 3). It will beseen from the above that all three stop lugs can be convenientlyproduced by punching and bending operations which contributes to thevery low cost of manufacture of the device. Spring washers or theequivalent are suitably associated with the pin 7 in order to increasethe friction during pivoting of the book 10. This arrangement incombination with the presence of stop lug 15 is of particular valuewhere the hook 10 is mounted in a manner to be gravitationally returnedinto its obstructing position.

The embodiments of the invention described and illustrated in thedrawing have been chosen merely by way of example, and severalmodifications are possible. It may he stated, for example, that the pin7 may be replaced by a screw-threaded pin having a conically shapedneck. A third possibility would be to dispose the pin or screw concernedin such a way that its longitudinal axis will be parallel with that ofthe hook 10. Further, the pin head 8 may be formed as an eccentricadapted, as the contact pressure increases, to cooperate with the stoplug or with any suitable other part of the device.

I claim:

1. An electrical clip-type contact device, comprising: a contact memberhaving two parallel legs which are adapted to clamp a contact bladebetween them; a hooklike element pivotally attached to one of said legs,a studlike member carried by the other leg, said hook-like element beingmovable between a first position in which the opening between the twoextreme ends of said legs is unobstructed, and a second position inwhich said hook-like element is cooperating with said stud-like memberin order both to obstruct said opening, thereby preventing said contactblade from moving out through the same, and to augment the contactpressure between the blade and each of the clip legs, a rotatable pinserving as a pivot pin for said hook-like element; and an eccentriccarried by said rotatable pin, said eccentric being adapted to cooperatewith a pressure surface of said hook-like element for displacing saidhook-like element into its obstructing position.

2. A contact device according to claim 1 wherein a first stop lugadapted in cooperation with said pin to prevent rotation of the latterbeyond the angular position in which the contact pressure produced bysaid eccentric has its maximum value.

3. A contact device according to claim 2, wherein a second stop lugadapted in cooperation with said pin when rotated in a contact-pressurediminishing sense to carry with it said hook-like element so as to swingthe latter away from its obstructing position.

4. A contact device according to claim 3 wherein said stop lugs beingconstituted by tongues formed integral with said hook-like element bypunching and bending up from the plane thereof.

5. A contact device according to claim 4, wherein a third stop lugadapted to limit the angular movement of said hook-like element from itsobstructing position to a position in which its longitudinal axis isessentially parallel to that of the contact blade.

6. An electrical clip-type contact device, comprising: a generallyU-shaped contact member adapted to clamp a contact blade between thelegs of said contact member; a fixed stud-like member on a first of saidlegs of said contact member; a closure member pivotally mounted on theother of said legs of said contact member and adapted to pivot between aclosed position across the opening of said contact member and an openposition away from said opening; and pressure means operatively coupledto said closure member and adapted to pivot said closure member betweenits open and closed positions and apply pressure to said stud-likemember, thereby increasing the clamping pressure of said contact memberon said contact element, when said closure member is in said closedposition.

References Cited by the Examiner UNITED STATES PATENTS 1,917,862 7/1933Wadsworth 339253 EDWARD C. ALLEN, Primary Examiner.

PATRICK A. CLIFFORD, Examiner.

I. H. MCGLYNN, Assistant Examiner.

1. AN ELECTRICAL CLIP-TYPE CONTACT DEVICE, COMPRISING: A CONTACT MEMBERHAVING TWO PARALLEL LEGS WHICH ARE ADAPTED TO CLAMP A CONTACT BLADEBETWEEN THEM; A HOOKLIKE ELEMENT PIVOTALLY ATTACHED TO ONE OF SAID LEGS,A STUDLIKE MEMBER CARRIED BY THE OTHER LEG, SAID HOOK-LIKE ELEMENT BEINGMOVABLE BETWEEN A FIRST POSITION IN WHICH THE OPENING BETWEEN THE TWOEXTREME ENDS OF SAID LEGS IN UNOBSTRUCTED, AND A SECOND POSITION INWHICH SAID HOOK-LIKE ELEMENT IS COOPERATING WITH SAID STUD-LIKE MEMBERIN ORDER BOTH TO OBSTRUCT SAID OPENING, THEREBY PREVENTING SAID CONTACTBLACE FROM MOVING OUT THROUGH THE SAME, AND TO AUGMENT THE CONTACTPRESSURE BETWEEN THE BLADE AND EACH OF THE CLIP LEGS, A ROTATABLE PINSERVING AS A PIVOT PIN FOR SAID HOOK-LIKE ELEMENT; AND AN ECCENTRICCARRIED BY SAID ROTATABLE PIN, SAID ECCENTRIC BEING ADAPTED TO COOPERATEWITH A PRESSURE SURFACE OF SAID HOOK-LIKE ELEMENT FOR DISPLACING SAIDHOOK-LIKE ELEMENT INTO ITS OBSTRUCTING POSITION.